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https://hdl.handle.net/2440/28296
Type: | Conference paper |
Title: | Rainfall simulation underestimates runoff phosphorus concentrations from dairy pastures |
Author: | Dougherty, W. Fleming, N. Cox, J. Chittleborough, D. |
Citation: | SuperSoil 2004 [electronic resource] : 3rd Australian New Zealand Soils Conference, 5-9 December 2004, University of Sydney, Australia / Balwant Singh (ed.): CD-ROM, [6] p. |
Publisher: | The Regional Institute Ltd |
Publisher Place: | CD-ROM |
Issue Date: | 2004 |
ISBN: | 1920842268 |
Conference Name: | Australian New Zealand Soils Conference (3rd : 2004 : University of Sydney) |
Editor: | Singh, B. |
Statement of Responsibility: | Warwick J. Dougherty, Nigel K. Fleming, Jim W. Cox and David J. Chittleborough |
Abstract: | Concentrations of phosphorus (P) in runoff from intensively managed pastures such as those used for dairying are high. Soil P has a large influence on runoff P concentrations. The most common technique used to derive soil P–runoff P relationships is rainfall simulation. A project is underway to test the utility of combining soil P-runoff P relationships with landscape hydrological models to assist in identifying areas for priority remedial action to reduce runoff P losses. However, there have been conflicting reports on the reliability of rainfall simulation to predict runoff P concentrations under natural rainfall at broader scales, e.g. hill-slope or sub-catchment. This paper reports a comparison of two methods of measuring runoff P concentrations, a) large plots (1250 m2) with low intensity simulated rainfall (8 mm/hr) and, b) small plots (1.5 m2) with high intensity simulated rainfall (80 mm/hr). Measurements were made on two occasions and over a range of soil P concentrations. There was a highly significant (P<0.01) effect of the method of measuring runoff P concentration. Runoff P concentrations from the small plots were approximately half of those derived from large plots. We hypothesize that these differences are the result of differences in contact times between the P source and runoff. However, the processes of mobilisation and subsequent forms of P are similar for both methods. Rainfall simulation may be used in the prediction of runoff P concentrations at scales broader than plot, e.g. at hillslope, if the effect of hydrological and chemical interactions are considered. |
Keywords: | Phosphorus runoff scale hillslope plots mobilisation process |
Description (link): | http://www.regional.org.au/au/asssi/supersoil2004/ |
Published version: | http://www.regional.org.au/au/asssi/supersoil2004/s16/oral/1560_doughertyw.htm |
Appears in Collections: | Aurora harvest 2 Earth and Environmental Sciences publications Environment Institute publications |
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